1. Field of the Invention
This invention relates to a method for the production of pillared clay possessing a freely controlled amount of pillars. This invention, therefore, contributes to further enhancing the utility of the pillared clay as catalyst, carrier, adsorbent, or separating material.
2. Prior Art Statement
No technique has yet been established for controlling the amount of pillars in pillared clay.
Among the conventional methods for the production of pillared clay are included those which are disclosed in Japanese Patent Public Disclosure SHO 54-5884, Japanese Patent Public Disclosure SHO 54-16386, Japanese Patent Publication SHO 62-12172, and Japanese Patent Publication SHO 62-41167, for example.
The assignee of the invention of the subject patent application has won grant of U.S. Pat. Nos. 4,629,713, 4,753,908, and 4,839,318 for inventions relating to a method for the production of pillared clay.
In the patent specifications mentioned above, there are some references to the interlayer distance of the pillared clay but there is absolutely no mention of any technique for the control of the amount of pillars in the pillared clay.
The pillared clay is produced by a method which comprises mixing clay with a cationic oligomer as a precursor of pillars thereby causing the cation of the oligomer to exchange ion with the exchangeable cation of the clay.
In this method, a fixed interrelation exists between the ion-exchange capacity and the amount of pillars and an interrelation exists between the ion-exchange capacity and the cation-exchange capacity of the clay. Generally, clay possesses the cation-exchange capacity of a specific magnitude peculiar to the kind of clay to be used. Since the amount of pillars in clay is fixed by the kind of clay, the clay has not been allowed to acquire a desired amount of pillars.
In the circumstances, an earnest desire has been expressed in the industry for developing a method capable of producing pillared clay possessing a desired amount of pillars.